The second picture is image of White Dzambhala. Blue or turqoise dragon is a figure also in sache (tibetan geomancy or like in chinese feng shui).but more specifically I cant remember. maybe connection with nagas and wealth also.

The azure or turquoise dragon is the vehicle of many Buddhist protective deities, aquatic or storm gods, and guardians of treasure.

The text goes on suggesting that, as a treasure guardian, the Sino-Tibetan dragon may be related to the Indian Naga (with whom it also shares a strong affinity with weather control), just as Gert said above.

ཁོང་ཁྲོ་སློང་མཁན་མེད་ན། བཟོད་པ་སུ་ལ་སྒོམ།

When there is no one to provoke anger, how shall we practice patience?